A FLOATING TELESCOPE.

Gisborne Times, Volume XXVII, Issue 2452, 17 March 1909, Page 7

A FLOATING TELESCOPE.

A telescope that floats in a tank of water, instead of being mounted on a solid pier, has just been installed at the Harvard observatory. The instrument is of the reflecting type, and is the largest of its kind in the world, tlie object mirror being five feet across. - The instrument proper is mounted on a watertight cylindrical steel float, which is buoyed up by water in a concrete tank only slightly larger than the cylinder and shaped to fit it. The cylinder is inclined,, and serves as the paler axis of the telescope. • It does not float freely in the tank but has a delicate pivot at each end to hold and guide it. The water, however, bears all the weight, so that none of it rests .on the pivots. All movements of the telescope are regulated by electric motors. The great glass mirror is so arranged that it can easily be removed and resilvered whenever it grows dim, although its weight is about two tons. File whole instrument is mounted in tlie open, air, but the image is reflected to an eyepiece iu an adjoining building, where the observer sits. The telescope is expected to reveal stars of the seventeenth or eighteenth magnitude—possibly even fainter ones —and work may thus be done with it that would be impossible with any other instrument.